Of the family of the yet unnamed royal baby, Queen Elizabeth II is worth the most at $660 million, Wealth-X, a firm that researches ultra-high net worth individuals, estimates. Prince Charles is worth an estimated $370 million, Prince William is worth an estimated $20 million, while his brother Harry is estimated to have $16 million.

Wealth-X's figures do not include the possible inheritance of the Crown Jewels and the Royal Collection. The queen's income in 2014 is expected to rise by 15 percent to nearly $58 million after the Crown Estate reported an increase in profit in June.

David Friedman, president of Wealth-X, says the royal baby will wear a crown of heavy financial burden during his life, because he would inherit his family's wealth upon their deaths.

"Families with substantial wealth already face acute challenges in helping their children navigate the burden and expectations that can accompany that wealth," he said. "Place on top of that the double burden of royal protocol and expectations, Prince William and Kate will need a tight group of friends and community to provide an environment where the new Prince can flourish. Wealth amplifies what lies beneath an individual's character. It will be up to Prince William and Kate to ensure that the prince can withstand the 'weight of glory'."

As third in line to the British Crown, the baby is secure in its financial inheritance even with the likelihood of a proposed law, which is likely to be passed, that provides for equal primogeniture.

Elena Mauer, deputy editor at TheBump.com said, "The royal baby will inherit his family's wealth, just like Queen Elizabeth inherited her dad's estates and Prince William and Harry were given money from their mother upon her passing. But boy is it nice to be this royal baby! With possibly inheriting $1 billion, this will be the most a royal heir has ever received."